The invention pertains to limb prosthesis, and more specifically to a lower leg member for extending an amputee's shortened limb and for connecting at the lower end to a prosthetic foot. Prosthetic pylons must be strong enough to support the body weight of the person while providing the proper combination of stiffness, flexation and damping to simulate the natural human stride. More specifically, the requisite degree of stiffness in a pylon is required to return energy back to the stride of the wearer at "toe-off". Sufficient damping must be present in the pylon to absorb the shock that occurs at "heel strike" when the pylon is returning from deformation, primarily bending, along its longitudinal axis.
Support pylons comprised of stiffening fibers in a polymeric binding matrix are generally known. Known prior art pylons are generally solid members having the stiffening fibers located either on the exterior surface of, or interspersed homogeneously throughout, the pylon. Solid pylons having larger cross-sections are too stiff to simulate the natural human stride, while solid pylons having lesser cross-sections provide inadequate damping and are not compatible with the prosthetic foot clamps generally in use. Furthermore, in pylons having either stiffening fibers homogeneously dispersed therein or pylons having an exterior layer of stiffening fibers, the resulting overall stiffness of the pylons is not optimum. Stiffening fibers located at or near the exterior of the pylon tended to become ineffective after a short period of use because of repeated bending stress at the exterior of the pylon which is greater than the strain tolerance of the fibers. The above is true for substantially all of the fibers in the pylons having stiffening fibers located on or proximate their exterior surfaces and is also the case for the majority of the fibers in pylons having stiffening fibers homogeneously dispersed.